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Building a dome in SketchUp

There are a wealth of different dome structures built during history. In this SketchUp tutorial, we shall examine the different steps towards developing a dome with (eventually) pndentives, a drum and a cuplola (in Part #2) as we can see them starting from Ancient and Medieval times up to the Classic revival (or Classicism) of the late 17th to the 19th centuries.

During the process, we'll use quite basic tools to build simple, basic shapes these magnificent structures are built up from.

During this modelling session, it is again important to separate the boolean operations of the outer and inner shells of the dome, just like in the "Creating a Cross Vault" tutorial. Now I will demonstrate the use of the Solid tools (SketchUp Pro only) while modelling the outer shell and the traditional Intersect tools (SketchUp Free) when modelling the inner shell.

Setting up the Outer Shell

We start with four columns around a square again. Draw a square around the outermost corners of the columns and make it a group.

Building a dome in SketchUp step 01

From the corners, draw an arc and make sure it is along the blue axis (see the blue inferencing line) and that it is a half circle. 

Building a dome in SketchUp step 02

Connect the endpoints of the arc and draw a circle from the midpoint of the connecting edge to exactly the corner.

Building a dome in SketchUp step 03

Select the edges of the circle and use the Follow me tool to lather the half circle around the circle to create the outer shell. 

Building a dome in SketchUp step 04

If it comes out "inside out" (i.e. the back face outside), right click and "Reverse faces". 

Building a dome in SketchUp step 05

This step is only needed if you do it with the Solid tools: redraw an edge on the perimeter to close the dome's bottom so that it will be a "solid" group in the next step.

Building a dome in SketchUp step 06

Select the whole dome (triple click on it) and make it a group.

Building a dome in SketchUp step 07

Open the group containing our rectangle and PushPull it up enough so that it covers the dome completely. 

Building a dome in SketchUp step 08

Now we have two solids to operate with.

Building a dome in SketchUp step 09

Intersecting the Solids

If you have the Free version, you can skip this part and jump here.

If you have the Pro version, select the box then the Intersect tool...

Building a dome in SketchUp step 10

...and click on the dome. 

Building a dome in SketchUp step 11

Here we are with our outer shell. Create a new layer, put this outer shell on this layer and hide the layer for the time being. 

Building a dome in SketchUp step 12

Setting up the Inner Shell

Repeat the steps under "Setting up the Outer Shell" only that now we draw everything snapping to the inner corners of the columns.

Building a dome in SketchUp step 13

One thing is different: leave the back face upside now (as the front face surface of the dome will be inside, seen from below).

Building a dome in SketchUp step 14

Intersecting with the Traditional Intersect Tools

If you have the Pro version and use the Solid tools, you can now repeat these steps but if you wish to practice the traditional intersect tools (as we sometimes need to work with non-solids) or you have the Free version, explode both groups, right click and "Intersect with selected" (although in our case "with model" would just do the same).

Building a dome in SketchUp step 15

Now comes the tedious part: I have already removed the upper, remaining parts of the box. Select these side surfaces and delete them.

Building a dome in SketchUp step 16

Select the remaining parts of the face of the bottom circle (if there is any at all since for this part we did not need to create it)

Building a dome in SketchUp step 17

The remaining, stray edges are tedious to clean up so use ThomThom's Cleanup Plugin to get rid of them

Building a dome in SketchUp step 18

Removing the Side Panels

When done in either way, turn on your hidden layer with the outer shell and explode everything.

Building a dome in SketchUp step 19

From inside out, start PushPulling the inner half circles. Make sure to snap to an outer edge or endpoint so that the PushPull tool stops exactly there and will cut the outer face properly.

Building a dome in SketchUp step 20

After the first PushPull (which establishes the distance you PushPulled), you can simply double click on the other faces to speed up this operation. 

Building a dome in SketchUp step 21

Finally select the remaining faces and connecting edges and delete them. 

Building a dome in SketchUp step 22

A little clean-up: right click on a front face and "Orient faces" to reverse those back faces under the arches.

Building a dome in SketchUp step 23

Select all (triple click), right click again and "soften/Smooth edges; you will probably only need to "touch" that slider a bit to soften the hard edges under the arches again...

Building a dome in SketchUp step 24

Group the whole thing...

Building a dome in SketchUp step 25

...but notice that it's not a "solid"

Building a dome in SketchUp step 26

Hide the columns (or see my tip at the end of this tutorial), open the group and cover the bottom of the "legs" of the dome.

Building a dome in SketchUp step 27

Now it is nice and solid... 

Building a dome in SketchUp step 28

This dome could be called a "hanging dome" (the English term "dome on pendentives" comes from the Latin "pndo" meaning "hang") but this bare kind of dome is rare in architecture however (or combined with cross ribs to form a so called "Romanesque cross vault" like in the Basilica of St Ambrose in Milan.

There is a setting under Window > Model info > Components to hide similar components (or groups) or the rest of the model while editing one. Now of course it is a tedious thing to open this panel every time you need it but you can easily assign a keyboard shortcut to these functions under Preferences > Shortcuts. I have Ctrl+H to hide the rest of the model and Shift+Ctrl+H to hide similar groups/components while editing one. This can speed up modelling parts that are covered by other objects - or inside a complex model generally.

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Comments   

 
#1 architex 2014-03-24 14:46
Nice tutorial... But, can you teach me how can I do the same, but in a elliptical dome? I need to do a structure for a elliptical dome.

Thanks.
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#2 budski82 2014-12-09 23:41
I to say thanks for taking the time. If it is a soap dish, tooth brush holder or the Eiffel Tower. Not understanding the tools use`s and work flow. Your doomed
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#3 budski82 2014-12-09 23:45
I also in-cooperated some of your technic`s from Gothic Window #1 to help create a boat hull. It is help from you and others alike that build confidence.
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